( Corrosion and Protection Research Laboratory,
Northwestern Polytechnical University, Xi'an 710072, China)
摘 要: 利用高频疲劳实验机和自制高温微动疲劳装置，研究了温度、 位移幅度、 接触压力等因素在对Ti811钛合金高温微动疲劳（FF）行为的影响， 并通过形态特征分析， 研究了微动疲劳的失效机理。结果表明： 350 °C和500 °C的高温下， Ti811合金微动疲劳敏感性较高， 且随着温度的升高，微动疲劳的敏感性增强， 蠕变是高温下Ti811合金FF失效的重要影响因素； FF的寿命随着接触压力和位移幅度的变化均呈现出非单调的变化规律，原因是名义接触压力的变化改变了接触区应力分布、 应力集中状况和微动位移幅度大小， 进而影响FF裂纹萌生几率和扩展驱动力； 位移幅度变化影响了疲劳应力因素和磨损在FF过程中所起作用和机制。
关键字: 微动疲劳；高温； 钛合金； 磨损； 蠕变
（ Corrosion and Protection Research Laboratory,
Northwestern Polytechnical University, Xi'an 710072, China）
Abstract: The fretting fatigue (FF) behaviors of Ti811 alloy influenced by temperature, slip amplitude and contact pressure were investigated using high frequency fatigue machine and self-made high temperature apparatus. The FF mechanisms were discussed by observing fretting surface morphology features. The results show that FF sensitivity is high at both 350 °C and 500 °C. The higher the temperature is, the more sensitive the FF failure of the alloy. Creep is the important factor which influences FF failure process of Ti811 alloy at elevated temperature. The FF life of the alloy doesn't change in a monotone way with the increasing slip amplitude and contact pressure. This is due to the fact that slip amplitude affects the action of fatigue and wear in fretting process, the nominal contact pressure affects the distribution and concentration of stress and fretting slip amplitude value at contact surface, further influences crack initiation probability and propagation driving force.
Key words: fretting fatigue; elevated temperature; titanium alloy; wear; creep
